Dimeric isoflavones

ABSTRACT

A compound of the general formula (I) or (II) wherein X is O, NR 4  or S and R 1 -R 8  are as defined in the specification

FIELD OF THE INVENTION

The present invention generally relates to novel dimeric molecules based on the 1,2-diphenylpropane (isoflavonoid) ring structure. The present invention further relates to the synthesis of the dimeric isoflavonoid molecules, compositions containing the same and their use as therapeutic agents.

BACKGROUND OF THE INVENTION

Naturally-occurring plant isoflavones are known to possess a wide range of fundamental biological effects on human cells including anti-oxidation and the up-regulation and down-regulation of a wide variety of enzymes and signal transduction mechanisms. Mitotic arrest and cytotoxicity of human cancer cells, increased capillary permeability, increased cellular adhesion, increased response of vascular smooth muscle cells to vaso-relaxants, and agonism of estrogen receptors, are just a few examples of the responses of animal cells to the biological effects of naturally-occurring isoflavonoids.

A range of therapeutic benefits as a result of these biological outcomes have been identified including the treatment and prevention of pre-menopausal symptoms such as pre-menstrual syndrome, endometriosis, uterine fibroids, hyperlipidaemia, cardiovascular disease, menopausal symptoms such as osteoporosis and senile dementia, alcoholism, benign prostatic hypertrophy, and cancers such as prostate, breast and large bowel carcinomas [see WO 93/23069; WO 96/10341; U.S. Pat. No. 5,424,331; JP 62-106017; JP 62-106016; U.S. Pat. No. 5,516,528; JP 62-106016A2; JP 62-106017A2; JP 61-246124; WO 98/50026; WO 99/43335; WO 00/49009; WO 00/644,438; WO 99/48496].

While over 700 different naturally occurring isoflavones are described, only a few are confirmed as having potential therapeutic benefits in animals including humans. These include daidzein, genistein, formononetin, biochanin and glycitein. These and all naturally occurring isoflavones are found in nature as the monomeric form either in a free state, or, more likely, bound to a carbohydrate moiety (glycoside). The isoflavone has to be separated from this moiety before it becomes biologically active.

A number of compounds with a structure related to naturally occurring plant isoflavones are also described as having biological properties with potential therapeutic benefit to animals including humans. These include compounds that are naturally occurring metabolites of plant isoflavones produced by bacterial fermentation by gut flora and embrace compounds such as equol and O-desmethylangolensin [WO 93/23069; WO 98/08503; WO 01/17986; WO 00/66576]. Also included in this group is the synthetic isoflavonoid ipriflavone, which is developed for the treatment of postmenopausal osteoporosis [WO 91/14429] and a wide range of synthetic isoflavonoid analogues [WO 98/08503].

Recently, some interest has been expressed in the biological properties of dimeric forms of isoflavonoids. Four forms of bis-isoflavones with the following structures are claimed to have 5-alpha-reductase inhibitory activity useful for the treatment of prostatomegaly [JP 9067362-A].

A C—C bridged bis-isoflavone dimer as shown below has also been described, but no biological activity or therapeutic benefit has been ascribed to it [Al-Maharik et al].

A requirement accordingly exists for new generation compounds that exhibit important pharmacological effects for use as prophylactics and in therapy.

SUMMARY OF THE INVENTION

Surprisingly, the present inventors have discovered a new class of molecules based on dimeric isoflavone compounds and derivatives. The dimeric molecules of the present invention generally show strong binding affinity for both estrogen receptors and hence exhibit remarkable physiological activity.

Thus according to a first aspect of the present invention there is provided a compound of the general formulae (I) or (II):

wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)H, OC(O)R₉, OS(O)R₉, OSi(R₁₀)₃, C(O)R₁₁, CO₂R₁₂, alkyl, haloalkyl, aryl, arylalkyl, thio, alkylthio, amino, alkylamino, dialkylamino, nitro or halo, R₉ is alkyl, haloalkyl, aryl, arylalkyl or alkylaryl, R₁₀ is independently hydrogen, alkyl or aryl, R₁₁ is hydrogen, alkyl, aryl, arylalkyl or an amino acid, and R₁₂ is hydrogen, alkyl, haloalkyl, aryl or arylalkyl, x is O, NR₄ or S, and the drawing “

” represents either a single bond or a double bond, which compounds include pharmaceutically acceptable salts thereof, with the proviso that in formula (1) at least one of R₅, R₆, R₇ and R₈ is hydrogen.

According to a second aspect of the present invention there is provided a process for the preparation of a compound of formulae (I) or (II) by reacting a compound of the formula (III)

wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)H, OC(O)R₉, OS(O)R₉, OSi(R₁₀)₃, C(O)R₁₁, CO₂R₁₂, alkyl, haloalkyl, aryl, arylalkyl, thio, alkylthio, amino, alkylamino, dialkylamino, nitro or halo, R₉ is alkyl, haloalkyl, aryl, arylalkyl or alkylaryl, R₁₀ is independently hydrogen, alkyl or aryl, R₁₁ is hydrogen, alkyl, aryl, arylalkyl or an amino acid, and R₁₂ is hydrogen, alkyl, haloalkyl, aryl or arylalkyl, OR₁₃ is hydroxy, another leaving group or an electron withdrawing group, x is O, NR₄ or S, and the drawing “

” represents either a single bond or a double bond, which compounds include pharmaceutically acceptable salts thereof, with the proviso that in the preparation of compounds of formula (I) at least one of R₅, R₆, R₇ and R₈ is hydrogen, with a coupling agent.

It has surprisingly been found by the inventors that isoflavone dimers of the general Formulae (I) and (II) have particular utility and effectiveness in the treatment, prophylaxis, amelioration defence against, and/or prevention of one of more of the following diseases and disorders (for convenience hereinafter referred to as the “therapeutic indications”):

-   -   (a) all forms of cancer (pre-malignant, benign and malignant) in         all tissues of the body. In this regard, the compounds may be         used as the sole form of anti-cancer therapy or in combination         with other forms of anti-cancer therapy including but not         limited to radiotherapy and chemotherapy;     -   (b) diseases and disorders associated with inflammatory         reactions of an abnormal or prolonged nature in any of the         body's tissues including but not limited to rheumatoid artritis,         tendonitis, inflammatory bowel disease, ulcerative colitis,         Crohn's Disease, sclerosing cholangitis;     -   (c) papulonodular skin lesions including but not limited to         sarcoidosis, angiosarcoma, Kaposi's sarcome, Fabry's Disease     -   (d) papulosquamous skin lesions including but not limited to         psoriasis, Bowen's Disease, and Reiter's Disease;     -   (e) actinic damage characterized by degenerative changes in the         skin including but not limited to solar keratosis,         photosensitivity diseases, and wrinkling;     -   (f) diseases and disorders associated with abnormal angiogenesis         affecting any tissue within the body including but not limited         to hemangiomas and telangiectasia;     -   (g) proliferative disorders of bone marrow including but not         limited to megaloblastic disease, myelodysplastic syndromes,         polycythemia vera, thrombocytosis and myelofibrosis;     -   (h) autoimmune disease characterized by abnormal immunological         responses including but not limited to multiple sclerosis, Type         1 diabetes, systemic lupus erythematosis, and biliary cirrhosis;     -   (i) neurodegenerative diseases and disorders characterized by         degenerative changes in the structure of the neurological system         including but not limited to Parkinson's Disease, Alzheimer's         Disease, muscular dystrophy, Lou-Gehrig Disease, motomeurone         disease;     -   (j) diseases and disorders associated with degenerative changes         within the walls of blood vessels including but not limited to         atherosclerosis, atheroma, coronary artery disease, stroke,         myocardial infarction, hypertensive vascular disease, malignant         hypertension, thromboangiitis obliterans, fibromuscular         dysplasia;     -   (k) diseases and disorders associated with abnormal         immunological esponses including but limited to dermatomyositis         and scleroderma;     -   (l) diseases and disorders associated with degenerative changes         within the eye including but not limited to cataracts, macular         degeneration, retinal atrophy.

In particular the isoflavone dimers also surprisingly have been found to have a potent effect on the production and function of reproductive hormones such as estrogens and androgens. As a result of this, these compounds may be used in the treatment and prevention of one or more of the following disorders and diseases:

-   -   (a) conditions in women associated with abnormal         estrogen/androgen balance including but not limited to cyclical         mastalgia, acne, dysmenorrhoea, uterine fibroids, endometriosis,         ovarian cysts, premenstrual syndrome, acute menopause symptoms,         osteoporosis, senile dementia, infertility; and     -   (b) conditions in men associated with abnormal estrogen/androgen         balance including but not limited to benign prostatic         hypertrophy, infertility, gynecomastia, alopecia hereditaria and         various other forms of baldness.

Thus, according to a third aspect of the present invention there is provided a method for the treatment, prophylaxis or amelioration of a disease or disorder which method includes the step of administering a therapeutically effective amount of one or more compounds of formulae (I) and (II) to a subject.

According to a fourth aspect of the present invention there is provided the use of one or more compounds of formulae (I) and (II) in the manufacture of a medicament for the treatment of disease.

According to a fifth aspect of the present invention there is provided the use of one or more compounds of formulae (I) and (II) as an anti-estrogen or selective estrogen receptor modulator (SERM).

According to a sixth aspect of the present invention there is provided an agent for the treatment, prophylaxis or amelioration of a disease which agent comprises one or more compounds of formulae (I) or (II).

According to a seventh aspect of the present invention there is provided a pharmaceutical composition which comprises one or more compounds of formulae (I) and. (II) in association with one or more pharmaceutical carriers and/or excipients.

According to a eighth aspect of the present invention there is provided a drink or food-stuff, which contains one or more compounds of formulae (I) and (II).

Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

DETAILED DESCRIPTION OF THE INVENTION

The dimeric molecules of the present invention are structurally related to monomeric isoflavone compounds and derivatives thereof. The term “isoflavone” as used herein is to be taken broadly to include ring-fused benzopyran molecules having a pendent phenyl group from the pyran ring based on a 1,2-diphenylpropane system. Thus, the classes of compounds generally referred to as isoflavones, isoflavenes, isoflavans, isoflavanones, isoflavanols and the like are generically referred to herein as isoflavones, isoflavone derivatives or isoflavonoid molecules.

The term “alkyl” is taken to mean both straight chain and branched chain alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secbutyl, tertiary butyl, and the like. The alkyl group has 1 to 10 carbon atoms, preferably from 1 to 6 carbon atoms, more preferably methyl, ethyl propyl or isopropyl. The alkyl group may optionally be substituted by one or more of fluorine, chlorine, bromine, iodine, carboxyl, C₁-C₄-alkoxycarbonyl, C₁-C₄-alkylamino-carbonyl, di-(C₁-C₄-alkyl)-amino-carbonyl, hydroxyl, C₁-C₄-alkoxy, formyloxy, C₁-C₄-alkyl-carbonyloxy, C₁-C₄-alkylthio, C₃-C₆-cycloalkyl or phenyl.

The term “aryl” is taken to include phenyl and naphthyl and may be optionally substituted by one or more C₁-C₄-alkyl, hydroxy, C₁-C₄-alkoxy, carbonyl, C₁-C₄-alkoxycarbonyl, C₁-C₄-alkylcarbonyloxy or halo.

The term “halo” is taken to include fluoro, chloro, bromo and iodo, preferably fluoro and chloro, more preferably fluoro. Reference to for example “haloalkyl” includes monohalogenated, dihalogenated and up to perhalogenated alkyl groups. Preferred haloalkyl groups are trifluoromethyl and pentafluoroethyl.

The compounds of the invention include all salts, such as acid addition salts, anionic salts and zwitterionic salts, and in particular include pharmaceutically acceptable salts.

The term “pharmaceutically acceptable salt” refers to an organic or inorganic moiety that carries a charge and that can be administered in association with a pharmaceutical agent, for example, as a counter-cation or counter-anion in a salt. Pharmaceutically acceptable cations are known to those of skilled in the art, and include but are not limited to sodium, potassium, calcium, zinc and quaternary amine. Pharmaceutically acceptable anions are known to those of skill in the art, and include but are not limited to chloride, acetate, citrate, bicarbonate and carbonate.

Dimeric isoflavone molecules and derivatives have only recently appeared in the literature.

Japanese patent application No. JP 9067362-A (Sankyo Co. Ltd.) describes bis-isoflavones joined either by the pendent phenyl groups or by one pendent phenyl group of one monomer to the aromatic benzopyran ring of the other isoflavone monomer. The bis-isoflavones are though to be useful as 5-alpha reductase inhibitors.

The synthesis of C—C bridged bis-isoflavones has also been described by the nucleophilic substitution of 2-bromomethyl isoflavone derivatives (Al-Maharik et al.). The double alkylation reaction gives rise to bridged bis-isoflavones attached through the 2-methyl groups. No activity has been ascribed to these newly synthesised bis-isoflavones.

In contrast, the dimeric molecules of the present invention are linked through the 4-position of the isoflavone pyran ring to either of the two aromatic rings. That is, the 4-position of the pyran ring is linked to the aromatic benzopyran ring (formula I), or to the pendent phenyl group (formula I).

Preferred dimeric molecules of the present invention are depicted by the general formulae (Ia) and (IIa):

wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)H, OC(O)R₉, OS(O)R₉, OSi(R₁₀)₃, C(O)R₁₁, CO₂R₁₂, alkyl, haloalkyl, aryl, arylalkyl, thio, alkylthio, amino, alkylamino, dialkylamino, nitro or halo, R₉ is alkyl, haloalkyl, aryl, arylalyl or alkylaryl, R₁₀ is independently hydrogen, alkyl or aryl, R₁₁ is hydrogen alkyl, aryl, arylalkyl or an amino acid, and R₁₂ is hydrogen, alkyl, haloalkyl, aryl or arylalkyl, X is O, NR₄ or S, and the drawing “

” represents either a single bond or a double bond, which compounds include pharmaceutically acceptable salts thereof, with the proviso that in Formula (Ia) at least one of R₅, R₆, R₇ and R₈ is hydrogen; more preferably they have the following substituents wherein R₁, R₂, R₃, R₄, R₅, R₇ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)R₉, OS(O)R₉, alkyl, aryl, arylalkyl, thio, alkylthio, bromo, chloro or fluoro, R₆ is hydrogen, R₉ is alkyl, fluoroalkyl or arylalkyl, and X is O; more preferably they have the following substituents wherein R₁ and R₆ are hydrogen, R₂, R₃, R₅ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)R₉, alkyl, aryl or arylalkyl, R₄ and R₇ are independently hydroxy, OR₉ or OC(O)R₉, R₉ is methyl, ethyl, propyl, isopropyl or trifluoromethyl, and X is O; and most preferably they have the following substituents wherein R₁ and R₆ are hydrogen, R₂, R₃, R₅ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)R₉ or methyl, R₄ and R₇ are independently hydroxy, OR₉ or OC(O)R₉, R₉ is methyl, and X is O.

Most preferably the novel dimeric compounds of formulae (I) and (II) are:

-   -   Tetraacetoxy 6-(4-(isoflavan-4′,7-diol))-isoflav-3-ene-4′,7-diol         (2)     -   6-(4-(Isoflavan-4′,7-diol))-isoflav-3-ene-4′,7-diol (3)     -   Tetraacetoxy 6-(4-(isoflavan-4′,7-diol))-isoflavan-4′,7-diol (4)     -   6-(4-(Isoflavan-4′,7-diol))-isoflavan-4′,7-diol (5)     -   6-(4-(4′,7-Dimethoxyisoflavan))-4′,7-dimethoxyisoflav-3-ene (6)     -   6-(4-(4′,7-Dimethoxyisoflavan)-4′,7-dimethoxyisoflavan (7)     -   Tetraacetoxy         3′-(4-(isoflavan-4′,7-diol))-isoflav-3-ene-4′,7-diol (8)     -   3′-(4-(Isoflavan-4′,7-diol))-isoflav-3-ene-4′,7-diol (9)     -   Tetraacetoxy 3′-(4-(isoflavan-4′,7-diol))-isoflavan-4′,7-diol         (10)     -   3′-(4-(Isoflavan-4′,7-diol))-isoflavan-4′,7-diol (11)

Compounds 2-11 are depicted by the following structural formulae:

Without wishing to be limited to theory, it is believed that the dimeric molecules of the present invention are formed as a result of an electrophilic aromatic substitution of one of the aromatic rings. Generally, plant-based isoflavone compounds have hydroxy groups in the 4′- and 7-positions, at least, on the isoflavone skeleton. These electron donating groups are thought to assist the electrophilic aromatic substitution and to direct substitution ortho or para to the electron donating substituent.

In a particularly preferred embodiment of the invention, the isoflavone diacetoxy tetrahydrodiadzein (1), R=Ac, is coupled to form a dimeric molecule upon dehydration of the monomer with phosphorus pentoxide.

Electrophilic substitution of the ring-fused benzene ring of (1) occurs preferentially alpha to the 7-oxy substituent and beta to the ring junction. The beta position is thought to be more available due to smaller steric constraints than that of the position alpha to the ring junction. The pyran oxygen is thought to assist in the selectivity of substitution by activation of the ring fused benzene to electrophilic aromatic substitution, in preference to substitution of the pendent phenyl group.

Other synthetic methods well known to those skilled in the art may also be employed in the synthesis of the dimeric molecules of the present invention. Such other suitable synthetic methods include Friedel-Crafts alkylation coupling of two isoflavones or derivatives thereof. Typical Friedel-Crafts reaction conditions are used with reagents such as aluminium chloride, boron trifluoride or similar Lewis acid catalysts. The coupling reaction is not limited to Friedel-Crafts type conditions, but may include other reaction conditions that can generate a “carbocation” species such as the conversion of a secondary alcohol to a phosphinic ester or similar facile leaving group. Oxidative coupling reaction conditions such as hydrogen peroxide, dilute permanganate, phosphorous pentoxide or other oxidative compounds may also be employed in the synthesis of the dimeric molecules of the invention.

Linking two monomeric isoflavone compounds or derivatives with a bridging group may also lead to dimeric isoflavone molecules of the present invention Suitable divalent bridging groups include, for example, —O—, —S—, —CH₂—, —(C(R)H)_(n)—, —NR—, or —C═O.

Chemical functional group protection, deprotection, synthons and other techniques known to those skilled in the art may be used where appropriate to aid in the synthesis of the compounds of the present invention, and their starting materials.

The preferred starting isoflavone monomer, diacetoxy tetrahydrodaidzein (1) R=Ac, may be obtained by standard procedures known in the art. Particular reference is made to published International patent applications WO 98/08503 and WO 00/49009, and references cited therein, (Novogen Research Pty Ltd) for useful synthetic methods for the production of (1) and related isoflavones.

However, the isoflavone monomers for use in the present invention may be derived from any number of sources readily identifiable to a person skilled in the art. By way of example, the isoflavones may be purchased commercially or extracted from plant sources. Those skilled in the art will readily be able to identify suitable plant species which may be used to derive suitable isoflavone extracts for use in the present invention, however, plants of particular use in the invention include chickpea, soy and clover species, for example. More preferably, an isoflavone extract is obtained from red clover or subterranean clover species.

An isoflavone extract may be prepared by any number of techniques known in the art. For example, suitable isoflavone extracts may be prepared by water/organic solvent extraction from the native plant source. It will be appreciated that an isoflavone extract may be prepared from any single tissue of a single species of plant or a combination of two or more different tissues thereof. Similarly, an extract may be prepared from a starting material which contains a heterogeneous mixture of tissues from two or more different species of plant.

Generally, where an isoflavone extract is prepared from plant material, the material may be comminuted or chopped into smaller pieces, partially comminuted or chopped into smaller pieces and contacted with water and an organic solvent, such as a water miscible organic solvent. Alternatively, the plant material is contacted with water and an organic solvent without any pre-treatment. The ratio of water to organic solvent may be generally in the range of 1:10 to 10:1 and may, for example, comprise equal proportions of water and solvent, or from 1% to 30% (v/v) organic solvent. Any organic solvent or a mixture of such solvents may be used. The organic solvent may preferably be a C2-10, more preferably a C1-4 organic solvent (such as methanol, chloroform, ethanol, propanol, propylene glycol, erythrite, butanol, butanediol, acetonitrile, ethylene glycol, ethyl acetate, glycidol, glycerol dihydroxyacetone or acetone). Optionally the water/organic solvent mixture may include an enzyme which cleaves isoflavone glycosides to the aglycone form. The mixture may be vigorously agitated so as to form an emulsion. The temperature of the mix may range, for example, from an ambient temperature to boiling temperature. Exposure time may be between one hour to several weeks. One convenient extraction period is twenty-four hours at 90° C. The extract may be separated from undissolved plant material and the organic solvent removed, such as by distillation, rotary evaporation, or other standard procedures for solvent removal. The resultant extract containing water soluble and non-water soluble components may be dried to give an isoflavone-containing extract, which may be formulated with one or more pharmaceutically acceptable carriers, excipients and/or auxiliaries according to the invention.

An extract made according to the description provided in the previous paragraphs may contain small amounts of oil which include isoflavones in their aglycone form (referred to herein as isoflavones). This isoflavone enriched oil, may be subject to HPLC to adjust the isoflavone ratios, or, if it is at the desired isoflavone ratio, may be dried, for example in the presence of silica, and be formulated with one or more carriers, excipients and/or auxiliaries to give an isoflavone containing extract. Alternatively, the isoflavones contained in said small amounts of oil may be further concentrated by addition to the oil of a non-water soluble organic solvent such as hexane, heptane, octane acetone or a mixture of one or more of such solvents. One example is 80% hexane, 20% acetone w/w having high solubility for oils but low solubility for isoflavones. The oil readily partitions into the organic solvent, and an enriched isoflavone containing extract falls out of solution. The recovered extract may be dried, for example in an oven at 50° C. to about 120° C., and formulated with one or more pharmaceutically acceptable carriers, excipients and/or auxiliaries.

Other suitable methods may be found in, for example, Chang et al which discloses methods appropriate for the synthesis of various isoflavones and derivatives thereof.

The dimeric isoflavone structures depicted in formulae (Ia) and (IIa) possess an inherent ability to restrict the conformation between the two monomeric structures to an orthogonal relationship. It is hypothesised that the apparent greater conformational rigidity of the orthogonal relationship and the inherent ability to define a displacement of H bond donors in the ligand binding domain monomeric section of the dimer leads to moderation of the normal agonistic actions of the monomer for cellular receptors. In most cases that moderation results in up-regulation of the biological activity, while in some cases it results in down-regulation of that activity. That is, the biological profile of the monomer which to a large extent is predictable based on the known structure-function relationship established from the experience with screening large libraries of such compounds, is unpredictable with the dimeric forms. Functions which are moderated with the conversion from the monomeric to the dimeric forms are as follows: absolute levels of agonism and antagonism of hER-α and HER-β as well as the relative levels of agonism/antagonism of both receptor types; inhibition of 5-α-reductase and 17β-steroidaldehydrogenase; anti-oxidation; mitotic arrest and induction of apoptosis of cancer cells; prostaglandin and inflammatory cytokine release; vasoactivity; high density lipoprotein and low density lipoprotein levels.

Thus the present inventors have surprisingly found that the dimeric molecules of the present invention present a family of new compounds that are indicated for the treatment and prevention of a range of important human diseases and disorders set out above. These diseases and disorders include cancers, inflammatory disorders, autoimmune disorders, cardiovascular disorders, and disorders associated with estrogen receptor activation.

In particular, the dimeric compounds of the present invention through their potent ability to inhibit proliferation of cancer cells and to induce apoptosis show use in the prevention and treatment of cancers, a term which any person skilled in the art would understand embraces aberrant growth of both a benign and malignant nature of any or all tissues in the body across epithelial, mesenchymal and neural types. This includes, but is not restricted to, carcinomas, adenocarcinomas, sarcomas, blastomas, adenomas, lymphomas, leukaemias, gliomas and melanoma.

In particular, the dimeric compounds of the present invention through their potent ability to act as h-ERβ agonists are able to provide oestrogenic support in particular to women of peri-menopausal and menopausal age and to prevent and to treat problems generally recognised as representing acute withdrawal of steroidal estrogen such as vasomotor symptoms (hot flushes and night sweats) and emotional symptoms (anxiety, depression, mood swings), problems generally recognised as representing sub-acute withdrawal of steroidal estrogen such as urinary incontinence and bladder prolapse, and problems generally recognised as representing chronic withdrawal of steroidal estrogen such as osteopaenia and osteoporosis, and senile dementia

In particular, the dimeric compounds of the present invention through their potent ability to act as h-ERα antagonists are able to prevent or to treat conditions in pre-menopausal women generally regarded as being associated with excessive stimulation of h-ERα receptors and leading to such conditions as cyclic mastalgia, endometriosis, endometrial hyperplasia, uterine fibroids, polycystic ovarian disease, and pre-menstrual syndrome.

In particular, the dimeric compounds of the present invention through their potent ability to induce vasodilation and to reduce vasospasm show use in the treatment and prevention of disorders generally recognised as being associated with vasopression either causally or indirectly and embracing but not limited to hypertension and migraine headache.

In particular, the dimeric compounds of the present invention through their potent ability to antagonise inflammatory processes and to moderate immunological processes show use in the prevention and treatment of disorders generally recognised as being associated with excessive inflammation or dysfunctional immune function and embracing but not limited to inflammatory conditions of the gastrointestinal tract including inflammatory bowel disease, ulcerative colitis, Crohn's disease, and sclerosing cholangitis, and inflammatory disorders of synovial membranes including rheumatoid arthritis.

In particular, the dimeric compounds of the present invention through their potent ability to act as anti-oxidants show use in the prevention and treatment of conditions generally recognised as being associated with oxidation leading to degenerative changes and including but not limited to conditions such as cataracts, actinic damage, and atherosclerosis.

In particular, the dimeric compounds of the present invention through their potent ability to inhibit androgenesis show use in the prevention and treatment of conditions generally recognised as being associated (either causally or indirectly) with aberrant function of androgens and including but not limited to male pattern baldness (alopecia hereditaria) and prostatic adenoma.

The amount of one or more compounds of formulae I and II which is required in a therapeutic treatment according to the invention will depend upon a number of factors, which include the specific application, the nature of the particular compound used, the condition being treated, the mode of administration and the condition of the patient. Compounds of formulae I or II may be administered in a manner and amount as is conventionally practised. See, for example, Goodman and Gilman, The Pharmacological Basis of Therapeutics, 1299 (7th Edition, 1985). The specific dosage utilised will depend upon the condition being treated, the state of the subject, the route of administration and other well known factors as indicated above. In general, a daily dose per patient may be in the range of 0.1 mg to 2 g; typically from 0.5 mg to 1 g; preferably from 20 mg to 200 mg.

The production of pharmaceutical compositions for the treatment of the therapeutic indications herein described are typically prepared by admixture of the compounds of the invention (for convenience hereafter referred to as the “active compounds”) with one or more pharmaceutically or veterinarially acceptable carriers and/or excipients as are well known in the art.

The carrier must, of course, be acceptable in the sense of being compatible with any other ingredients in the formulation and must not be deleterious to the subject. The carrier or excipient may be a solid or a liquid, or both, and is preferably formulated with the compound as a unit-dose, for example, a tablet, which may contain from 0.5% to 59% by weight of the active compound, or up to 100% by weight of the active compound. One or more active compounds may be incorporated in the formulations of the invention, which may be prepared by any of the well known techniques of pharmacy consisting essentially of admixing the components, optionally including one or more accessory ingredients.

The formulations of the invention include those suitable for oral, rectal, optical, buccal (for example, sublingual), parenteral (for example, subcutaneous, intramuscular, intradermal, or intravenous) and transdermal administration, although the most suitable route in any given case will depend on the nature and severity of the condition being treated and on the nature of the particular active compound which is being used.

Formulation suitable for oral administration may be presented in discrete units, such as capsules, sachets, lozenges, or tablets, each containing a predetermined amount of the active compound; as a powder or granules; as a solution or a suspension in an aqueous or non-aqueous liquid; or as an oil-in-water or water-in-oil emulsion. Such formulations may be prepared by any suitable method of pharmacy which includes the step of bringing into association the active compound and a suitable carrier (which may contain one or more accessory ingredients as noted above). In general, the formulations of the invention are prepared by uniformly and intimately admixing the active compound with a liquid or finely divided solid carrier, or both, and then, if necessary, shaping the resulting mixture such as to form a unit dosage. For example, a tablet may be prepared by compressing or moulding a powder or granules containing the active compound, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing, in a suitable machine, the compound of the free-flowing, such as a powder or granules optionally mixed with a binder, lubricant, inert diluent, and/or surface active/dispersing agent(s). Moulded tablets may be made by moulding, in a suitable machine, the powdered compound moistened with an inert liquid binder.

Formulations suitable for buccal (sublingual) administration include lozenges comprising the active compound in a flavoured base, usually sucrose and acacia or tragacanth; and pastilles comprising the compound in an inert base such as gelatin and glycerin or sucrose and acacia.

Compositions of the present invention suitable for parenteral administration conveniently comprise sterile aqueous preparations of the active compounds, which preparations are preferably isotonic with the blood of the intended recipient. These preparations are preferably administered intravenously, although administration may also be effected by means of subcutaneous, intramuscular, or intradermal injection. Such preparations may conveniently be prepared by admixing the compound with water or a glycine buffer and rendering the resulting solution sterile and isotonic with the blood. Injectable formulations according to the invention generally contain from 0.1% to 60% w/v of active compound and are administered at a rate of 0.1 ml/minute/kg.

Formulations suitable for rectal administration are preferably presented as unit dose suppositories. These may be prepared by admixing the active compound with one or more conventional solid carriers, for example, cocoa butter, and then shaping the resulting mixture.

Formulations or compositions suitable for topical administration to the skin preferably take the form of an ointment, cream, lotion, paste, gel, spray, aerosol, or oil. Carriers that may be used include Vaseline, lanoline, polyethylene glycols, alcohols, and combination of two or more thereof. The active compound is generally present at a concentration of from 0.1% to 0.5% w/w, for example, from 0.5% to 2% w/w. Examples of such compositions include cosmetic skin creams.

Formulations suitable for transdermal administration may be presented as discrete patches adapted to remain in intimate contact with the epidermis of the recipient for a prolonged period of time. Such patches suitably contain the active compound as an optionally buffered aqueous solution of, for example, 0.1 M to 0.2 M concentration with respect to the said active compound.

Formulations suitable for transdermal administration may also be delivered by iontophoresis (see, for example, Panchagnula et al) and typically take the form of an optionally buffered aqueous solution of the active compound. Suitable formulations comprise citrate or Bis/Tris buffer (pH 6) or ethanol/water and contain from 0.1 M to 0.2 M active ingredient.

The active compounds may be provided in the form of food stuffs, such as being added to, admixed into, coated, combined or otherwise added to a food stuff. The term food staff is used in its widest possible sense and includes liquid formulations such as drinks including dairy products and other foods, such as health bars, desserts, etc. Food formulations containing compounds of the invention can be readily prepared according to standard practices.

Formulations suitable for inhalation may be delivered as a spray composition in the form of a solution, suspension or emulsion. The inhalation spray composition may further comprise a pharmaceutically acceptable propellant such as carbon dioxide or nitrous oxide.

The compositions of the invention may also be administered to a human in a dietary supplement form. Dietary supplements incorporating the actives can be prepared by adding the composition to a food in the process of preparing the food. Any food may be used including, but not limited thereto, meats such as ground meats, emulsified meats and marinated meats; beverages such as nutritional beverages, sports beverages, protein fortified beverages, juices, milk, milk alternatives, and weight loss beverages; cheeses such as hard and soft cheeses, cream cheese, and cottage cheese; frozen desserts such as ice cream, ice milk, low fat frozen desserts, and non-dairy frozen desserts; yogurts; soups; puddings; bakery products; salad dressings; and dips and spreads such as mayonnaise, margarine, butter, butter substitute, and other fat containing spreads. The composition is added to the food in an amount selected to deliver a desired dose of the composition to the consumer of the food.

Compounds of the present invention have potent antioxidant activity and thus find wide application in pharmaceutical and veterinary uses, in cosmetics such as skin creams to prevent skin ageing, in sun screens, in foods, health drinks, shampoos, and the like.

It has surprisingly been found that compounds of the formulae I or II interact synergistically with vitamin E to protect lipids, proteins and other biological molecules from oxidation.

Accordingly a further aspect of this invention provides a composition comprising one or more compounds of formulae I and II, vitamin E, and optionally a pharmaceutically, veterinarially or cosmetically acceptable carriers and/or excipients.

Therapeutic methods, uses and compositions may be for administration to humans or animals, such as companion and domestic animals (such as dogs and cats), birds (such as chickens, turkeys, ducks), livestock animals (such as cattle, sheep, pigs and goats) and the like.

As used herein, the term “treatment” is to be considered in its broadest context. The term does not necessarily imply that an animal is treated until total recovery. Accordingly, “treatment” includes amelioration of the symptoms or severity of a particular condition or preventing or otherwise reducing the risk of developing a particular condition.

A “pharmaceutically acceptable carrier, excipient, auxiliary and/or diluent” as used herein should be taken to include any carrier, excipient, auxiliary or diluent that is considered useful in preparing a pharmaceutical composition. Such carriers, excipients, auxiliaries or diluents will be generally safe, non-toxic and neither biologically nor otherwise undesirable. The term also includes carriers, excipients, auxiliaries or diluents that are acceptable for veterinary use as well as human pharmaceutical use. As used herein the term “pharmaceutically acceptable carriers, excipients, auxiliaries and/or diluents” includes one of, or more than one of, such substances.

The invention is further described with reference to the following non-limiting examples.

EXAMPLES Example 1 Synthesis of Tetra-acetoxy 6(4-(isoflavan-4′,7-diol))-isoflav-3-ene-4′,7-diol (2)

A mixture of approximately 1:1 cis-and trans-diacetoxytetrahydrodaidzein (1) (300 g) is dissolved in dry dichloromethane and stirred under a bed of nitrogen at 15° C. until all material has dissolved. Phosphorous pentoxide (500 g) is added quickly with vigorous stirring and the reaction is continued for 4-6 hours. The reaction mixture is then filtered through a bed of silica gel with the dimeric structure having a lower R_(f) than the monomeric side product. The dimeric compound is further purified by selective recrystallisation from ethyl acetate.

¹H NMR (CDCl₃, 400 MHz): 7.40 (2H, d, J=8 Hz), 7.15 (2H, d, J=8 Hz), 7.13 (2H, d, J=8 Hz), 7.05 (2H, d, J=8 Hz), 6.90 (1H, d J=7.6 Hz), 6.75 (1H, d, J=1.5 Hz), 6.65 (1H, bs s), 6.63 (1H, br s), 6.60 (1H, dd, J=7.6, 1.5 Hz), 6.58 (1H, br s), 5.05 (2H, brs), 4.38 (1H, dd, J=9,3 Hz), 4.30 (1H br d, J=7 Hz), 4.25 (1H, dd, J=9,6 Hz), 3.38 (1H, m), 2.32 (3H, s), 2.30 (3H, s) 2.28 (3H, s), 2.08 (3H, br s)

Example 2 Synthesis of 6(4-(isoflavan-4′,7-diol))-isoflav-3-ene-4′,7-diol (3)

Imidazole (0.166 g) was added to a suspension of tetra-acetoxy 6(4-(isoflavan-4′,7-diol))-isoflav-3-ene-4′,7-diol (0.2 g) in absolute ethanol (2.0 ml). The mixture was refluxed under nitrogen for 12 hours. The solution was concentrated under vacuum and the product was precipitated by addition of deionised water (10 ml). The mixture was left in the fridge overnight. The off-white solid was filtered and freeze-dried to afford (0.1 g, 67%) of the free phenolic dimeric compound.

¹H NMR (D6-DMSO, 400 MHz): 9.1 (4H, br, OH), 7.26 (2H, d, J=7.6 Hz), 7.04 (2H, d, J=7.6 Hz), 6.72 (2H, d, J=7.6 Hz), 6.61 (1H, s), 6.60 (2H, d, J=7.6 Hz), 6.56 (1H, s), 6.46 (1H, d, J=8 Hz), 6.25 (1H, s), 6.22 (1H, brd, J=8 Hz), 6.20 (1H, brs), 4.95 (2H, s), 4.44 (1H, d, J=8.4 Hz), 4.13 (1H, dd, J=11, 3.3 Hz), 4.06 (1H, dd, J=11, 7.7 Hz), 3.28 (1H, ddd, J=8.4, 7.7, 3.3 Hz).

Example 3 Estrogen Receptor Binding Assay

The ability of the tetraphenolic dimer (Structure 3) and tetraacetoxy dimer (Structure 2) to interact with estrogen receptor alpha and beta was determined using a commercially available estrogen receptor binding kit. This kit employs a competitive binding assay to determine the relative binding affinity of test compounds for recombinant human estrogen receptors-alpha (ER-α) and beta (ER-β). Briefly, recombinant human estrogen receptor alpha or beta is added to fluorescently labelled estrogen ligand to form an estrogen ligand/receptor complex which exhibits high fluorescence polarization. The complex is then added to decreasing concentrations of competitor test compounds. The shift in polarization in the presence of test compound is used to determine the relative affinity of test compounds for the estrogen receptor. When assayed using the manufacturer's specifications, we determined the concentration of estradiol required to displace 50% of bound fluorescent estrogen ligand (EC₅₀) at 0.011 μM for ER-alpha and 0.006 μM for ER-beta which is in agreement with published values (Bolger et al., 1998). The tetraphenolic dimer (Structure 3) demonstrated equal binding affinity for estrogen receptor alpha and beta (ER-α 0.35±0.05 μM; ER-β 0.37±0.05 μM.), however the tetraacetoxy dimer (Structure 2) did not bind either receptor.

Example 4 Anticancer Activity

The anticancer potential of the tetraphenolic dimer (Structure 3) and the tetraacetoxy dimer (Structure 2) was assessed using a panel of human tumour cell lines, including glioma (C6), prostate (PC3), breast (MCF-7), soft tissue (Kym-1) and lung (NCI-H23 and NCI-H460). The cell cytotoxicity assay was conducted as per the method of Alley et al., 1988. Cell lines are exposed to varying concentrations of test compound for a fixed time. At the conclusion of the assay, the viability of the cell population is determined using the hydrogen acceptor reagent 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT). The concentration of compound required to inhibit 50% of cell growth in comparison to a control (IC₅₀) is an indicator of effectiveness of the compound. (i.e. the lower the concentration of compound required to inhibit 50% of normal cell proliferation, the more efficacious). Both dimers exhibited potent anticancer activity against the cancer types tested (Table 1).

TABLE 1 IC50 determinations for both dimeric isoflavones against tumour cell lines. Cell Line IC50 (μM) C6 Dimer MCF-7 PC3 Glioma Kym-1 NCI-H460 NCI-H23 Structure 3 18 ± 2 13.5 17.5 3.2 14.4 13.5 Structure 2 10 ± 5 6 NT NT NT 7.3 NT = not tested

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications. The invention also includes all of the steps, features, compositions and compounds referred to or indicated in this specification individually or collectively, and any and all combinations of any two or more of said steps or features.

REFERENCES

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1. A compound selected from general formula (Ia):

wherein R₁, R₄, R₅, R₇ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)R₉, OS(O)R₉, alkyl, aryl, arylalkyl, bromo, chloro or fluoro, R₂, R₃, and R₆ are hydrogen, R₉ is alkyl, fluoroalkyl or arylalkyl, and X is O, and the drawing “

” represents either a single bond or a double bond, which compounds include pharmaceutically acceptable salts thereof.
 2. The compound of claim 1, wherein R₁ is hydrogen, R₅ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)R₉, alkyl, aryl or arylalkyl, R₄ and R₇ are independently hydroxy, OR₉ or OC(O)R₉, and R₉ is methyl, ethyl, propyl, isopropyl or trifluoromethyl.
 3. The compound of claim 2, wherein R₅ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)R₉ or methyl, and R₉ is methyl.
 4. A compound of claim 3 selected from: Tetraacetoxy 6-(4-(isoflavan-4′,7-diol))-isoflav-3-ene-4′,7-diol (2), 6-(4-(Isoflavan-4′,7-diol))-isoflav-3-ene-4′,7-diol (3), Tetraacetoxy 6-(4-(isoflavan-4′,7-diol))-isoflavan-4′,7-diol (4), 6-(4-(Isoflavan-4′,7-diol))-isoflavan-4′,7-diol (5), 6-(4-(4′,7-Dimethoxyisoflavan))-4′,7-dimethoxyisoflav-3-ene (6), and 6-(4-(4′,7-Dimethoxyisoflavan))-4′,7-dimethoxyisoflavan (7).
 5. A process for the preparation of a compound of formula (Ia)

which process comprises reacting a compound of the formula (III)

wherein R₁, R₄, R₅, R₇ and R₈ are independently hydrogen, hydroxy, OR₉, OC(O)R₉, OS(O)R₉, alkyl, aryl, arylalkyl, bromo, chloro, or fluoro, R₂, R₃, and R₆ are hydrogen, R₉ is alkyl, fluoroalkyl, or arylalkyl, and X is O, and the drawing “

” represents either a single bond or a double bond, with a coupling agent to prepare the compound of formula (Ia).
 6. The process of claim 5, wherein the compound of formula (Ia) is as defined in any one of claims 3 to
 6. 7. The process of claim 5, wherein the coupling agent is phosphorus pentoxide, hydrogen peroxide, permanganate or a Lewis acid.
 8. A composition which comprises one or more compounds of formula (Ia) as defined in claim 1 in association with one or more pharmaceutical carriers and/or excipients.
 9. A composition comprising one or more compounds of formula (Ia) as defined in claim 1, vitamin E, and optionally a pharmaceutically, veterinarially or cosmetically acceptable carriers and/or excipients. 